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This is a 28-year-old African American male with history of HIV(+) status. The patient is said to have good CD4 count. He complains of blurred vision in the right eye. Fundus pictures are shown above. The patient denies any other ocular complaints.

1.	Which of the following would be in the differential diagnosis?
	e -- On the fundus examination the view is hazy secondary to significant vitritis. Also vascular sheathing is observed. The retina specialist has also noted snowbanks inferiorly as an additional finding, although these are not shown in the pictures. The differential diagnosis could be divided into two main groups: -Non HIV related uveitis: Syphilis, sarcoidosis, HLA-B27, toxoplasmosis, tuberculosis, pars planitis -HIV related uveitis: Cytomegalo virus, Cryptococcus (typically choroiditis), pneumocystis (choroiditis), lymphoma, acute retinal necrosis (with normal to high CD4 counts), progressive outer retinal necrosis (low CD4 counts), immune recovery uveitis, HIV retinitis, rifabutin or cidofovir toxicity (anterior segment more involved).
2.	Which laboratory tests would be helpful in this case?
	e -- Due to the long differential diagnosis list, all of the above laboratory tests are needed (RPR and FTA-Ab for syphilis, ACE for sarcoidosis, and CD4 count for immune status). RPR is typically positive in syphilis although it can be negative. It can also be markedly elevated due to polyclonal B cell activity.  The FTA-antibody test is usually positive, but becomes non-reactive after treatment in 38% of AIDS patients.
3.	What other information would be helpful for this case?
	a -- In this case, the patient did have a positive RPR and FTA-antibody test.  This is typically associated with syphilis. The patient also had dermatological findings in the hands suggestive of syphilis. Prior laboratory values are important to compare CD4 counts and prior syphilis blood test results. It is important to know if the patient is taking antiviral treatment against HIV especially if a patient has low CD4 counts. This patient had been RPR negative one year prior to the present findings. The patient was started on a course of intravenous ceftriaxone by the infectious disease specialist. Syphilis can occur with CD4 counts higher than 200. Syphilis may also  be a presenting illness in cases of HIV. Patients with syphilis have an increased chance of having AIDS and vice versa. If the patient has one disease, he should be tested for the other. Also, syphilis can be reactivated in HIV patients. Some other clinical findings of with syphilis would be iritis, vitritis, retrobulbar optic neuritis, perineuritis, neuroretinitis, retinal vasculitis, necrotizing retinitis, and exudative retinal detachment. Ocular syphilis is associated with neurosyphilis in 85+% of cases. Patients like this with retinitis or vitritis should be treated in a similiar manner as those patient with neurosyphilis. Typical treatment is intravenous penicillin. Twelve-24 million units should be administered for 10 days. Maintanance treatment is not recommended. Frequent failure is seen with intramuscular penicillin treatment in immunocompromised hosts.